Three Allied forces agents, named Miller, Hoan and Frick, were having dinner in their hotel in Seydisfjordur, Iceland, on the evening of May 5, 1944, when they got wind of the scheme.

A seal hunter had spotted three strangers behaving suspiciously near Borgarfjordur.

The agents tried to alert an Allied ship anchored off the coast in that area but were told it could take hours before it got up enough steam to sail, by which time the men could be deep into the Icelandic wilderness.

So they persuaded the seal hunter to be their guide, borrowed a boat and in the early hours of the morning landed near where the men had been seen.

They hiked across the snow, through the night, following the faint trail left by the spies until finally, at 6am the following day, they spotted them.

Their report notes: ''We cocked our pistols and quickened our pace.''

They surrounded the men, who very quickly confessed to being German soldiers, but claimed they had been sent only to gather meteorological information.

Ernst Fresenius, an avowed Nazi loyalist, was in fact the only German. The other two men, Hjalti Bjornsson and Sigurdur Juliusson, were Icelanders who had been hired as mercenaries by the Nazi military.